Syntax

	tagextract [-h][-v][-n number ][-m [ fieldname op [fieldvalue]]]...
        [infile][outfile]

Description

tagextract processes a tag stream on its standard input, looking for records which match the conditions required by the fieldname, operator and usually fieldvalue arguments.

Modifier flags

-h
Disables normal header processing. If this is not present then the first record is assumed to be a header, and will always be output intact as the new header record.
-v
Invert the sense of matching, to output all the lines which do NOT match the conditions.
-d
Print debugging information to stderr
-n
Output the record which is this number of records into the tag file later versions may expand this to select a range. Record 0 is the header.

Conditions

Most condition tests are of the form
	fieldname operator value
but some do not require the value. The operators are
-eq
String equals
==
Numerically equal (like in Perl)
-gt
Numerically greater than (unlike Perl)
-lt
Numerically less than (unlike Perl)
-contains
Contains
-exists
True if the field exists in the record - does not take a value
-before
True if the field with the given value has not yet been reached